Thermostat



Aug- 2, 1955 F. REINGRUBER ETAL 2,714,526

THERMOSTAT original Filed oct. 2e, 1945 United States Patent OTHERMOSTAT Frank Rengruber, Yonkers, and Joseph Reingruber, Astoria, N.Y.

Original application October 26, 1945, Serial No. 624,674, now PatentNo. 2,584,924, dated February 5, 1952. Divided and this applicationJanuary 5, 1952, Serial No. 265,144

1 claim. (Cl. 297-11) This invention relates to thermostats and moreparticularly to that type in which is employed two metals of dissimilarheat expansion characteristic to actuate a control, whether an electricswitch, relay valve or the like and is a division of our applicationSer. No. 624,674, led October 26, 1945, Patent No. 2,584,924, datedFebruary 5,

Our invention contemplates the provision of a comparatively sensitivethermostat so designed and constructed that the relatively smallmovement of the expanding metal is translated into a larger, multipliedor magniied movement of the control operating element and thereforeprovides a thermostat that reacts rapidly to relatively small changes intemperature.

Our invention further contemplates a thermostat of such constructionthat it may be readily applied in direct contact with the device to thetemperature of which the thermostat is designed to react, and therebyone adapted to quickly react to relatively small changes in temperaturethereof, thereby increasing the sensitivity of regulation and limitingthe tendency of the device to overshoot the temperature for which thethermostat is set.

Our invention still further contemplates the provision of a thermostatwhich is simple and rugged in construction, that may be convenientlyapplied as a unit to the article, the temperature of which is to beregulated.

Our invention also contemplates the provision of such a thermostaticunit that is relatively small in size and compact, reliable inoperation.

Other and further objects and advantages of the present invention andthe uses to which it may be put as well as the devices to which it maybe applied will be clear from the description which follows and thedrawing appended thereto, in which drawing, reference characters areused to designate similar parts.

Fig. 1 is a schematic elevation of the temperature responsive mechanismof our invention.

Fig. 2 is an exaggerated schematic illustration of the expansioncharacteristics of the temperature responsive mechanism according to ourinvention.

Referring now to the drawing, we have there illustrated a thermostatwhich as a unit may be secured in any suitable manner to a surface 14,of the device, the temperature of which is to be regulated.

The temperature responsive mechanism according to our invention, of athermostat unit 10, is provided with the flat bar 12, of metal, having arelatively high coefcient of expansion, such as brass or aluminum, whichbar is mounted on, in contact with the surface 14.

In the illustration, the control operating member 24, which is exed bythe expansion of the linearly expanding member is secured at the ends ofits legs 26 and 28, preferably as by spot welding to the linearlyexpansible member 12.

The member 24, is collapsed or exed by the outward pull on toes 108 and110, imposed thereon by the expansion of the bar 12, to which they havebeen secured as by the welds 118, to thereby separate the legs and lowerthe center portion of the member which opens the switch means. Themember 24, in the embodiment illustrated, has at the ends of its legs 26and 28, sharp bends which form the toes 108 and 110.

As a result, the legs 26 and 28, will ex or curve concavedly adjacenttheir connection and curve convexedly upward at the toe ends asillustrated by the broken lines in Fig. 2.

This further adds to the magnitude of the downward movement for a givenexpansion of the bar 12, making the thermostat the more sensitive.

In this construction, the exed member 24, positively moves the arm 144,down as the member is collapsed or exed by the expansion of the bar 12,to which the toe elements 108 and 110 of the legs 26 and 28 are secured.

The arm 144 is normally tensioned against the member 24 in the crotchformed where the inclined legs 26 and 28 meet and may be operativelyconnected to a valve, indicator, relay, etc., to operate it.

Any suitable conventional tension means and construction which will urgethe arm 144 in the normal position illustrated may be used and since itforms no part of our invention details thereof need not be given, aspring and pivot connection to the arm, serving as an example.

As the bar 12, which is in good thermal contact with the device, withwhich the thermostat is associated, expands, the arm 144 is positivelyoperated by the thereby flexed member 24, to open or close a valve,operate a relay or indicator, etc.

Upon cooling, the bar 12 contracts, returning the member 24 to itsoriginal shape and position thereby permitting the tensioned arm 144 toreturn to its normal position.

As illustrated in the schematic drawing of Fig. 2, the central portionof the member 24 at line of bend F, is drawn downwardly from F to G bythe expansion of the expansible member from H to I, the legs also exingalong the concaVo-convex curve at I, because originally they werestraight and the spring member sharply bent at its centre and at thetoes and which assumed curvilinear shape also adds to the multipliedlowering of the line of bend.

The relative dimensions of the various elements of the temperatureresponsive mechanism used with any embodiment of our invention will varyin practice.

It will be seen that we have provided a sensitive thermostat in which arelatively small linear movement of a heat expanded member is translatedinto a comparatively greater, multiplied or magnified movement of themember controlling the operation of the device.

It is further apparent that we have provided a thermostat in which thetemperature responsive mechanism comprises a member that readily expandsor contracts under the inuence of changes in temperature to ex a secondmember which is spaced from it except at its ends, to

thereby operate a control.

It is still further apparent that we have provided a simple, rugged,self-contained, compact and relatively small thermostat that is reliablein operation and readily adjustable.

While we have illustrated a specific embodiment of our invention, we donot intend to be limited to the specific details shown, but intend toclaim our invention as broadly as the prior art and the scope of theappended claim permit.

We claim:

In a thermostat a linearly expansible and contractible bar having arelatively high coeflicient of expansion, a spring member having a lowercoeficient of expansion, said spring member being sharply bent at itscenter in the form of a crotch and having a straight leg extending fromeach side of the crotch to the bar, each leg terminating at the end in asharply bent toe secured in at engagement on an end of the bar and anelement arranged in the crotch and tensioned against the spring member,said element being movable with the spring member upon the expansion andcontraction of the bar, each leg of the spring membery being normallystraight at one temperature and under expansion of the bar with increasein temperature being convexly curved adjoining the toes andconcavelycurved adjoining'the crotch, thereby effecting magnifiedmovement of the crotch toward the bar and whereby relatively smalllinearexpansion of the bar is translated Vinto greater amplified movement atthe crotch for accomplishing a sensitive, more rapid action of theelement controlled by said crotch.

References Cited in the le of this patent UNITED STATES PATENTS FOREIGNPATENTS vGermany Jan. 24, 1930

